CPTSV(l) ) CPTSV(l)NAME
CPTSV - compute the solution to a complex system of linear equations
A*X = B, where A is an N-by-N Hermitian positive definite tridiagonal
matrix, and X and B are N-by-NRHS matrices
SYNOPSIS
SUBROUTINE CPTSV( N, NRHS, D, E, B, LDB, INFO )
INTEGER INFO, LDB, N, NRHS
REAL D( * )
COMPLEX B( LDB, * ), E( * )
PURPOSE
CPTSV computes the solution to a complex system of linear equations A*X
= B, where A is an N-by-N Hermitian positive definite tridiagonal
matrix, and X and B are N-by-NRHS matrices. A is factored as A =
L*D*L**H, and the factored form of A is then used to solve the system
of equations.
ARGUMENTS
N (input) INTEGER
The order of the matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of
the matrix B. NRHS >= 0.
D (input/output) REAL array, dimension (N)
On entry, the n diagonal elements of the tridiagonal matrix A.
On exit, the n diagonal elements of the diagonal matrix D from
the factorization A = L*D*L**H.
E (input/output) COMPLEX array, dimension (N-1)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix A. On exit, the (n-1) subdiagonal elements of the unit
bidiagonal factor L from the L*D*L**H factorization of A. E
can also be regarded as the superdiagonal of the unit bidiago‐
nal factor U from the U**H*D*U factorization of A.
B (input/output) COMPLEX array, dimension (LDB,NRHS)
On entry, the N-by-NRHS right hand side matrix B. On exit, if
INFO = 0, the N-by-NRHS solution matrix X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, the leading minor of order i is not positive
definite, and the solution has not been computed. The factor‐
ization has not been completed unless i = N.
LAPACK version 3.0 15 June 2000 CPTSV(l)
